[OpenMP] Add an additional test for D34888

Summary: Test for checking if the mapping is performed correctly. This is a test initially included in Patch https://reviews.llvm.org/D29905

Reviewers: Hahnfeld, carlo.bertolli, caomhin, ABataev

Reviewed By: Hahnfeld

Subscribers: tra, cfe-commits

Differential Revision: https://reviews.llvm.org/D38040

llvm-svn: 314303